freundTech
Tried it, didn't work
Set up as described in the extra help. After setup:
dbus-send --print-reply --type=method_call --dest=org.mpris.MediaPlayer2.spotpris.device5d81cefb30a5337f5dcd7af052f3a1b0fc1935c3 /org/mpris/MediaPlayer2 org.freedesktop.DBus.Properties.Get string:org.mpris.MediaPlayer2.Player string:Volume
Error org.freedesktop.DBus.Error.ServiceUnknown: The name org.mpris.MediaPlayer2.spotpris.device5d81cefb30a5337f5dcd7af052f3a1b0fc1935c3 was not provided by any .service files
What's the "extra help?"
What does playerctl -l show? playerctl
Is spotify actively playing something (not paused?)
Is there any output from the spotpris2 process?
Spotify shows up in playerctl. I can use sp and other tools with it no problem. It's running in memory, but frozen with no output. Doesn't matter if something is playing or not.
It looks like playerctl is not seeing spotpris2 -- so where did you get that device name from (device5d81cefb30a5337f5dcd7af052f3a1b0fc1935c3)?
Can you try making this change, to see if you're really being affected by #8 here? I'd guess it's not that, since you don't have any error output, but it's still worth a check.